1. Field of the Invention
The present invention generally relates to an apparatus and method for transmitting and receiving multimedia data, and more particularly to an interface apparatus and method for encapsulating various types of multimedia data and transmitting and receiving the encapsulated multimedia data between devices on a network aimed at multimedia transmission.
2. Description of the Related Art
For efficient transmission of various multimedia contents, MPEG (Moving Picture Experts Group) has developed a variety of standards, such as MPEG2 TS (Transport Stream) and MP4 systems and file formats. Further, standards organizations, such as IETF (Internet Engineering Task Force) and IEEE (Institute of Electrical and Electronic Engineers) 3GPP (3rd Generation Partnership Project), have developed a variety of protocols for transmission of various multimedia content on the Internet, and platform technologies for configuring a multimedia content use the MPEG standards.
As the trend toward convergence of broadcast and communication services has continued since 2000, an environment has emerged where various content and services must be transmitted through different networks. Further, due to advances in content compression and transmission technologies, and improvements in display performance (e.g. TV), users desire to use high-definition data at a lower cost.
In order to meet the above requirements, MPEG intends to develop a standard technology that enables efficient transmission of a high-definition multimedia content, converged transmission of various multimedia contents, and use of various networks in transmission of a multimedia content.
FIG. 1 illustrates a conventional multimedia content transmission structure in which different protocols are used according to various multimedia content.
Referring to FIG. 1, each application (e.g. e-mail, file transfer, web service, etc.) is conventionally serviced in a corresponding layer by using a separate protocol. For example, an e-mail service 101 requires the SMTP protocol 103 in the application layer, requires the TCP protocol 105 in the transport layer, and requires the IP protocol 107 in the network layer. To the contrary, a voice service 113 requires the RTP protocol 115 in the application layer, and requires the UDP protocol 117 in the transport layer.
For example, assume that movie content is provided to a user. One frame constituting the movie content typically includes a video stream, an audio stream, and caption information. In the case of using the protocol structure of FIG. 1, the video stream, the audio stream, and the caption information must be transmitted using different protocols, as mentioned above. Therefore, when the conventional protocol structure is used, content including various types of media (hereinafter referred to as “multimedia content”), such as movie content, is inefficient to transmit. That is, in the method in current use for providing multimedia content, separate protocols must be applied according to respective media constituting each multimedia content, which results in inefficiency in multimedia content transmission. In particular, there is difficulty in transmission of complex multimedia content including various multimedia contents.